I knew I shouldn’t have clicked on that link.

Of course, nobody knows for sure until we manage to decode the messages dogs send and receive via urine. But I watched the video at lower speed to see more of the adult dog’s body language. I’d guess that he’s an intact male, still quite young and not very self-assured, but used to making his own decisions. There’s a lot of posturing. His body is stiff the entire time, there’s even some visible piloerection (this is a sign of anxiety, not aggression). The dog displays very little contact with his humans.

The puppies likely smell like other adult dogs – they’re young enough to have only just left their mother and maybe even a whole group of adult dogs, possibly including females in heat and older males. I believe the inspection is more intense because of this. The fact that the pups are in a box exacerbates this. If they were allowed to move freely, they would likely roll over and lie still for the adult to sniff them from head to toe. They would also very clearly communicate that they are no threat.

So, in short: this inexperienced dog is in an extremely arousing situation, surrounded by a rich world of smells that are real to him, but invisible to us. The need to urinate immediately is not surprising, especially if this dog was left at home while the puppies were picked up. I don’t think he purposely peed on the pups, though there are dogs that will mark any visitor’s belongings. In this case, I think it’s more likely that the adult dog is successfully housetrained, but needs to pee urgently. He glances at his person for a second, and then pees on the one thing in the house that is not part of the home. The reason I think he’s peeing and not marking is that to mark, dogs tend to use just a couple of drops.

This type of introduction is unwise. It didn’t go very badly because the puppies are quite chill and the adult seems to be a generally friendly dog. But if they had met outside somewhere, with the adult on a leash and the puppies free to move around, they would all have felt more relaxed and the urine would have found its way onto a tree, not those unsuspecting pups.

I assume the dog is male and the puppies maybe smell like another male dog (maybe the father) and he’s trying to get rid of the smell of another male dog. At least that’s a theory. Or maybe he just doesn’t like them lol.